PeerJ Preprints: Paleontologyhttps://peerj.com/preprints/index.atom?journal=peerj&subject=2200Paleontology articles published in PeerJ PreprintsPaleontology of the Bears Ears National Monument: history of exploration and designation of the monumenthttps://peerj.com/preprints/34422017-12-012017-12-01Jessica UglesichRobert J GayM. Allison Stegner
Bears Ears National Monument (BENM) is a new, landscape-scale national monument jointly administered by the Bureau of Land Management and the Forest Service in southeastern Utah as part of the National Conservation Lands system. As initially designated, BENM encompasses 1.3 million acres of land with exceptionally fossiliferous rock units. These units comprise a semi-continuous depositional record from the Pennsylvanian Period through the middle of the Cretaceous Period. Additional Quaternary and Holocene deposits are known from unconsolidated river gravels and cave deposits. The fossil record from BENM provides unique insights into several important paleontological periods of time, including the Pennsylvanian-Permian transition from fully aquatic to more fully terrestrial tetrapods; the rise of the dinosaurs following the Triassic-Jurassic extinction; and the response of ecosystems in dry climates to sudden temperature increases at the end of the last ice age and across the Holocene. While the paleontological resources of BENM are extensive, they have historically been under-studied. Here we summarize prior paleontological work in BENM and review the data used to support paleontological resource protection in the 2016 BENM proclamation.

Bears Ears National Monument (BENM) is a new, landscape-scale national monument jointly administered by the Bureau of Land Management and the Forest Service in southeastern Utah as part of the National Conservation Lands system. As initially designated, BENM encompasses 1.3 million acres of land with exceptionally fossiliferous rock units. These units comprise a semi-continuous depositional record from the Pennsylvanian Period through the middle of the Cretaceous Period. Additional Quaternary and Holocene deposits are known from unconsolidated river gravels and cave deposits. The fossil record from BENM provides unique insights into several important paleontological periods of time, including the Pennsylvanian-Permian transition from fully aquatic to more fully terrestrial tetrapods; the rise of the dinosaurs following the Triassic-Jurassic extinction; and the response of ecosystems in dry climates to sudden temperature increases at the end of the last ice age and across the Holocene. While the paleontological resources of BENM are extensive, they have historically been under-studied. Here we summarize prior paleontological work in BENM and review the data used to support paleontological resource protection in the 2016 BENM proclamation.

Fossil fern rhizomes as a model system for biotic interactions across geologic time: Evidence from Patagoniahttps://peerj.com/preprints/34222017-11-212017-11-21Alexander C. BippusIgnacio H. EscapaPeter WilfAlexandru M. F. Tomescu
Background. A wealth of data on the networks of ecological interactions present in the modern biota can be readily obtained, due to the ease of unlimited access to the living organisms that form these networks. In contrast, understanding of such interactions in ecosystems of the geologic past is incomplete. Specifically, in terrestrial ecosystems we know comparatively little about plant biotic interactions besides herbivory, oviposition, galling. Here we describe a tiny in situ fossil community which sheds light on concurrent plant-plant, plant-fungal, and plant-animal interactions.
Methods. A single silicified osmundaceous rhizome from a new locality of the early Eocene (ca. 52 Ma) Tufolitas Laguna del Hunco was studied in serial thin sections using light microscopy. The community of organisms colonizing the tissues of the rhizome was characterized by identifying the organisms, as well as mapping and quantifying their distribution. For this, a 200 x 200 µm grid was superimposed onto the rhizome cross section and the colonizers present at each node of the grid were tallied.
Results. Preserved in situ, this community offers a rare window onto aspects of ancient ecosystems usually lost to time and taphonomic processes. The community is surprisingly diverse and includes the first fossilized leafy liverworts in South America, also marking the only fossil record of leafy bryophyte epiphytes; several types of fungal hyphae and spores; microsclerotia with probable affinities in several ascomycete families; and oribatid mite coprolites.
Discussion. The community associated with the Patagonian rhizome enriches our understanding of plant biotic interactions in the distant past and adds to a growing body of literature, which indicates that osmundaceous rhizomes were important hosts for component communities in ancient ecosystems, just as they are today. Because osmundaceous rhizomes represent an ecological niche that has remained unchanged over time and space, and are abundant in the fossil record, they provide a good paleoecological model system that could be used for exploring plant biotic interactions across geologic time.

Background. A wealth of data on the networks of ecological interactions present in the modern biota can be readily obtained, due to the ease of unlimited access to the living organisms that form these networks. In contrast, understanding of such interactions in ecosystems of the geologic past is incomplete. Specifically, in terrestrial ecosystems we know comparatively little about plant biotic interactions besides herbivory, oviposition, galling. Here we describe a tiny in situ fossil community which sheds light on concurrent plant-plant, plant-fungal, and plant-animal interactions.

Methods. A single silicified osmundaceous rhizome from a new locality of the early Eocene (ca. 52 Ma) Tufolitas Laguna del Hunco was studied in serial thin sections using light microscopy. The community of organisms colonizing the tissues of the rhizome was characterized by identifying the organisms, as well as mapping and quantifying their distribution. For this, a 200 x 200 µm grid was superimposed onto the rhizome cross section and the colonizers present at each node of the grid were tallied.

Results. Preserved in situ, this community offers a rare window onto aspects of ancient ecosystems usually lost to time and taphonomic processes. The community is surprisingly diverse and includes the first fossilized leafy liverworts in South America, also marking the only fossil record of leafy bryophyte epiphytes; several types of fungal hyphae and spores; microsclerotia with probable affinities in several ascomycete families; and oribatid mite coprolites.

Discussion. The community associated with the Patagonian rhizome enriches our understanding of plant biotic interactions in the distant past and adds to a growing body of literature, which indicates that osmundaceous rhizomes were important hosts for component communities in ancient ecosystems, just as they are today. Because osmundaceous rhizomes represent an ecological niche that has remained unchanged over time and space, and are abundant in the fossil record, they provide a good paleoecological model system that could be used for exploring plant biotic interactions across geologic time.

Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaurhttps://peerj.com/preprints/34152017-11-152017-11-15Michael P Taylor
Xenoposeidon proneneukos is a sauropod dinosaur represented by a single partial dorsal vertebra, NHMUK R2095, which consists of the centrum and the base of a tall neural arch. Despite its fragmentary nature, it is recognisably distinct from all other sauropods, and is here diagnosed with five unique characters. One character previously considered unique is here recognised as shared with Rebbachisaurus garasbae: an “M”-shaped arrangement of laminae on the lateral face of the neural arch. Following the more complete Rebbachisaurus garasbae, these laminae are now interpreted as ACPL and lateral CPRL, which intersect anteriorly; and PCDL and CPOL, which intersect posteriorly. Similar arrangements are also seen in some other rebbachisaurid specimens (though not all, possibly due to serial variation), but never in non-rebbachisaurid sauropods. Xenoposeidon is therefore referred to Rebbachisauridae. Due to its elevated parapophysis, the holotype vertebra is considered a posterior dorsal despite its elongate centrum. Since Xenoposeidon is from the from the Berriasian–Valanginian (earliest Cretaceous) Ashdown Beds Formation of the Wealden Supergroup of southern England, it is the earliest known rebbachisaurid by some 10 million years. Electronic 3D models were invaluable in determining Xenoposeidon's true affinities: descriptions of complex bones such as sauropod vertebrae should always provide them where possible.

Xenoposeidon proneneukos is a sauropod dinosaur represented by a single partial dorsal vertebra, NHMUK R2095, which consists of the centrum and the base of a tall neural arch. Despite its fragmentary nature, it is recognisably distinct from all other sauropods, and is here diagnosed with five unique characters. One character previously considered unique is here recognised as shared with Rebbachisaurus garasbae: an “M”-shaped arrangement of laminae on the lateral face of the neural arch. Following the more complete Rebbachisaurus garasbae, these laminae are now interpreted as ACPL and lateral CPRL, which intersect anteriorly; and PCDL and CPOL, which intersect posteriorly. Similar arrangements are also seen in some other rebbachisaurid specimens (though not all, possibly due to serial variation), but never in non-rebbachisaurid sauropods. Xenoposeidon is therefore referred to Rebbachisauridae. Due to its elevated parapophysis, the holotype vertebra is considered a posterior dorsal despite its elongate centrum. Since Xenoposeidon is from the from the Berriasian–Valanginian (earliest Cretaceous) Ashdown Beds Formation of the Wealden Supergroup of southern England, it is the earliest known rebbachisaurid by some 10 million years. Electronic 3D models were invaluable in determining Xenoposeidon's true affinities: descriptions of complex bones such as sauropod vertebrae should always provide them where possible.

Functional and morphometric analysis of a middle Miocene bandicoot (Marsupialia, Peramelemorphia) skeleton from the Riversleigh World Heritage Area, Australiahttps://peerj.com/preprints/33932017-11-062017-11-06Karen H BlackKenny J TravouillonTroy J MyersMichael ArcherSuzanne J HandLaura A B WilsonJoseph Bevitt
Peramelemorphia comprises four families: the extant Peramelidae (bandicoots), and Thylacomyidae (bilbies); the recently extinct Chaeropodidae (pig-footed bandicoot); and the extinct Yaralidae; with at least ten fossil species of uncertain familial affinity designated as Perameloidea incertae sedis. Extant taxa (18 species) are characteristically omnivorous, small to medium sized (0.1-4.9 kg) semi-fossorial/fossorial marsupials with a quadrupedal bounding gait. They occupy varied habitats from desert to rainforest in Australia and New Guinea. Fourteen pre-Pliocene taxa are currently described on the basis of cranial and/or dental material, yet none is known from its postcranial skeleton. Here we use qualitative morphological and morphometric data to analyse a partial skeleton of a new species of bandicoot from a middle Miocene cave deposit, AL90 Site, in the Riversleigh World Heritage Area. AL90 has been radiometrically dated at 14.7-15.1 Ma, however the species is abundant in numerous early to middle Miocene deposits at Riversleigh The AL90 specimen preserves the skull and dentaries, the fore-and hindlimbs, and elements of the manus, pes and axial skeleton. The species is estimated to have weighed approximately 300g (based on predictive marsupial craniodental regression equations) which is comparable among extant bandicoots to Perameles bougainville (Western barred bandicoot). Unlike modern species, the appendicular skeleton of the fossil taxon is less well-adapted for scratch-digging and fossorial behaviours. A striking contrast is the relatively elongate, gracile bones of the antebrachium of the fossil taxon compared with the generally short, robust forearm of modern bandicoots. Collectively, our data indicate a more generalized niche for this species than crown group peramelemorphians and may support suggestions that archaic bandicoots filled an ecological niche later dominated by small dasyurids during the late Cainozoic.

Peramelemorphia comprises four families: the extant Peramelidae (bandicoots), and Thylacomyidae (bilbies); the recently extinct Chaeropodidae (pig-footed bandicoot); and the extinct Yaralidae; with at least ten fossil species of uncertain familial affinity designated as Perameloidea incertae sedis. Extant taxa (18 species) are characteristically omnivorous, small to medium sized (0.1-4.9 kg) semi-fossorial/fossorial marsupials with a quadrupedal bounding gait. They occupy varied habitats from desert to rainforest in Australia and New Guinea. Fourteen pre-Pliocene taxa are currently described on the basis of cranial and/or dental material, yet none is known from its postcranial skeleton. Here we use qualitative morphological and morphometric data to analyse a partial skeleton of a new species of bandicoot from a middle Miocene cave deposit, AL90 Site, in the Riversleigh World Heritage Area. AL90 has been radiometrically dated at 14.7-15.1 Ma, however the species is abundant in numerous early to middle Miocene deposits at Riversleigh The AL90 specimen preserves the skull and dentaries, the fore-and hindlimbs, and elements of the manus, pes and axial skeleton. The species is estimated to have weighed approximately 300g (based on predictive marsupial craniodental regression equations) which is comparable among extant bandicoots to Perameles bougainville (Western barred bandicoot). Unlike modern species, the appendicular skeleton of the fossil taxon is less well-adapted for scratch-digging and fossorial behaviours. A striking contrast is the relatively elongate, gracile bones of the antebrachium of the fossil taxon compared with the generally short, robust forearm of modern bandicoots. Collectively, our data indicate a more generalized niche for this species than crown group peramelemorphians and may support suggestions that archaic bandicoots filled an ecological niche later dominated by small dasyurids during the late Cainozoic.

Quantifying geographic range measures and their utility as extinction risk proxieshttps://peerj.com/preprints/33792017-10-302017-10-30James Boyle
Geographic range is used as a correlate of extinction risk for extant and extinct organisms across the fields of conservation and paleobiology. However, the exact method used to measure geographic range, the biases, and the limitations of each are rarely discussed explicitly despite their potential to impact conclusions. Here I examine and quantify properties of five commonly used measures of geographic range (convex hull area, maximum pairwise great circle distance, latitudinal range, longitudinal range, and cell count) along with a rarely used measure (minimum spanning tree distance) in the context of three datasets. A simulated dataset of two shapes with known areal limits, a paleontological occurrence dataset of pre-Cenozoic brachiopod genera from the Paleobiology Database (PBDB), and 50000 occurrence records of birds species in the western hemisphere from the eBird database.
Simulated distributions indicate that when a distribution is simple (i.e. a rectangle) all measures are similarly accurate and precise at varying sample sizes and all measures converge toward the true value with increasing sample size. However, given a more complex distribution (i.e. horseshoe shape) the convex hull area becomes increasingly inaccurate as sample size increases even as it becomes more precise. Within the PBDB dataset the minimum spanning tree was heavily favored by Akaike Information Criterion as the most effective predictor of extinction risk. Analysis of the eBird data set indicated differences between IUCN Red List Categories were significant for all geographic range measures. Overall, these results suggest that for the purpose of categorical comparisons, such as those between victims and survivors of an extinction event, all six geographic range measures are interchangeable. However, the magnitude of the relationship between geographic range and extinction risk is strongly dependent on the choice of measure. Simple linear measures, such as latitudinal range, were relatively poor predictors while minimum spanning tree and cell count measures were strong predictors, especially after sampling was accounted for. The minimum spanning tree measure was found to perform at the same level or better than most other measures with the main drawback being that it is computationally expensive.

Geographic range is used as a correlate of extinction risk for extant and extinct organisms across the fields of conservation and paleobiology. However, the exact method used to measure geographic range, the biases, and the limitations of each are rarely discussed explicitly despite their potential to impact conclusions. Here I examine and quantify properties of five commonly used measures of geographic range (convex hull area, maximum pairwise great circle distance, latitudinal range, longitudinal range, and cell count) along with a rarely used measure (minimum spanning tree distance) in the context of three datasets. A simulated dataset of two shapes with known areal limits, a paleontological occurrence dataset of pre-Cenozoic brachiopod genera from the Paleobiology Database (PBDB), and 50000 occurrence records of birds species in the western hemisphere from the eBird database.

Simulated distributions indicate that when a distribution is simple (i.e. a rectangle) all measures are similarly accurate and precise at varying sample sizes and all measures converge toward the true value with increasing sample size. However, given a more complex distribution (i.e. horseshoe shape) the convex hull area becomes increasingly inaccurate as sample size increases even as it becomes more precise. Within the PBDB dataset the minimum spanning tree was heavily favored by Akaike Information Criterion as the most effective predictor of extinction risk. Analysis of the eBird data set indicated differences between IUCN Red List Categories were significant for all geographic range measures. Overall, these results suggest that for the purpose of categorical comparisons, such as those between victims and survivors of an extinction event, all six geographic range measures are interchangeable. However, the magnitude of the relationship between geographic range and extinction risk is strongly dependent on the choice of measure. Simple linear measures, such as latitudinal range, were relatively poor predictors while minimum spanning tree and cell count measures were strong predictors, especially after sampling was accounted for. The minimum spanning tree measure was found to perform at the same level or better than most other measures with the main drawback being that it is computationally expensive.

Sails at the water: ecological convergence between sphenacodontids and spinosaurids?https://peerj.com/preprints/29172017-10-052017-10-05Dawid Mazurek
Spinosaurids (Diapsida: Spinosauridae) and sphenacodontids (Synapsida: Sphenacodontidae) share not only a characteristic tall neural spines, but also an atypical – compared to their close respective relatives – ecology, i.e. apparently piscivorous and possibly semiaquatic mode of life. This similarity might hold clue for the role of their sails. It is here suggested that sails of these animals 1) served thermoregulatory function, warming the animals, otherwise submerged in the water, as well as 2) enabled them to hunt for fish in a way similar to the technique of Recent diapsid, black heron (Egretta ardesiaca).

Spinosaurids (Diapsida: Spinosauridae) and sphenacodontids (Synapsida: Sphenacodontidae) share not only a characteristic tall neural spines, but also an atypical – compared to their close respective relatives – ecology, i.e. apparently piscivorous and possibly semiaquatic mode of life. This similarity might hold clue for the role of their sails. It is here suggested that sails of these animals 1) served thermoregulatory function, warming the animals, otherwise submerged in the water, as well as 2) enabled them to hunt for fish in a way similar to the technique of Recent diapsid, black heron (Egretta ardesiaca).

Taphonomy and palaeoecology of the White Hunter Local Faunahttps://peerj.com/preprints/33142017-10-042017-10-04Troy Myers
The White Hunter (WH) Local Fauna (LF) is one of the oldest assemblages from the Riversleigh World Heritage Area, belonging to Faunal Zone A and tentatively dated at approximately 24 Ma. The mammalian fauna has many plesiomorphic taxa and a wide range of body sizes are represented, although it is depauperate in medium to large arboreal mammals and over-represented by small to medium-sized macropodoids, vombatomorphians and carnivores. The non-mammalian vertebrate fauna also covers a wide body size range.
The palaeoenvironmental conditions at the time of deposition have been contentious, ranging from hypotheses of cold and dry woodland to warm, wet rainforest, and many climatic and vegetation combinations in between. The autecologies of various species provide only equivocal support for palaeoenvironmental conclusions.
Taphonomic and palaeoecologic data were tested herein to further illuminate palaeoenvironmental understanding. Mammalian post-cranial elements were examined for degree of weathering, abrasion, fragmentation, taxonomic bias and susceptibility to transport. No obvious bias against small vertebrates was observed. The fauna does not appear to represent a mixed-assemblage. Animals most likely died within close proximity to the site of deposition, although the absence of scavenger/carnivore damage militates against predation as the main source of accumulation. Trampling of elements may have been significant.
Results suggest that WH may have been a moderately large ephemeral water body, subject to periodic drying and fed by a slow-moving creek. The climate was cooler than the early Miocene, with a distinct wet and dry season. Surrounding vegetation may have been a type without modern analogue combining structural, but not floristic, equivalents of open dry forest and closed rainforest. There is no evidence for gradational wet open forest types, but this may represent a rapid move to closed forest. These results are reinforced by palaeocommunity analysis of Riversleigh LFs which unite WH LF with a suite of early Miocene Lfs as a similar palaeocommunity type, perhaps antecedent to them.

The White Hunter (WH) Local Fauna (LF) is one of the oldest assemblages from the Riversleigh World Heritage Area, belonging to Faunal Zone A and tentatively dated at approximately 24 Ma. The mammalian fauna has many plesiomorphic taxa and a wide range of body sizes are represented, although it is depauperate in medium to large arboreal mammals and over-represented by small to medium-sized macropodoids, vombatomorphians and carnivores. The non-mammalian vertebrate fauna also covers a wide body size range.

The palaeoenvironmental conditions at the time of deposition have been contentious, ranging from hypotheses of cold and dry woodland to warm, wet rainforest, and many climatic and vegetation combinations in between. The autecologies of various species provide only equivocal support for palaeoenvironmental conclusions.

Taphonomic and palaeoecologic data were tested herein to further illuminate palaeoenvironmental understanding. Mammalian post-cranial elements were examined for degree of weathering, abrasion, fragmentation, taxonomic bias and susceptibility to transport. No obvious bias against small vertebrates was observed. The fauna does not appear to represent a mixed-assemblage. Animals most likely died within close proximity to the site of deposition, although the absence of scavenger/carnivore damage militates against predation as the main source of accumulation. Trampling of elements may have been significant.

Results suggest that WH may have been a moderately large ephemeral water body, subject to periodic drying and fed by a slow-moving creek. The climate was cooler than the early Miocene, with a distinct wet and dry season. Surrounding vegetation may have been a type without modern analogue combining structural, but not floristic, equivalents of open dry forest and closed rainforest. There is no evidence for gradational wet open forest types, but this may represent a rapid move to closed forest. These results are reinforced by palaeocommunity analysis of Riversleigh LFs which unite WH LF with a suite of early Miocene Lfs as a similar palaeocommunity type, perhaps antecedent to them.

Sublime recapitulation: Evolution of the appendicular skeleton of Australian Mekosuchinae crocodiles.https://peerj.com/preprints/32932017-09-282017-09-28Michael D Stein
Australian mekosuchines (Crocodylia; Crocodyloidea) with their wide diversity of cranial shape and inferred hunting strategies present a fascinating window into the diversification processes of crocodilians. This includes lingering questions as to the extent of any terrestrial habitus. A direct morphological signal for locomotion can be expected in the postcrania, particularly the girdles and the limbs of the appendicular skeleton. After a lengthy survey, enough materials of the pelvic girdle are available to chart morphological variation in the subfamily from Eocene through to middle Miocene. Over this period, the pelvis has undergone a vigorous morphological radiation. An enclosed, ventrally oriented acetabulum in the ilium developed in one lineage that apparently recapitulates the pillar-erect configuration of the pelvic girdle seen in many Mesozoic crocodilian lineages, suggesting consistent use of erect high-walk in these mekosuchines. Other pelves from Oligo–Miocene deposits display morphology closer to modern crocodilians despite clearly representing derived forms themselves, indicating a partition of locomotory strategy in the fauna during the Oligo–Miocene. While materials of hindlimb remain frustratingly lacking in light of this discovery, enough materials of forelimb humeri have been uncovered to chart the morphological variation in the subfamily from Eocene through to Pleistocene, corroborating what is seen in the pelvic girdle. As such, a collaborative project has been started that aims to quantitatively asses shape and stress variation in the mekosuchine forelimb using geometric morphometric and finite element analyses.

Australian mekosuchines (Crocodylia; Crocodyloidea) with their wide diversity of cranial shape and inferred hunting strategies present a fascinating window into the diversification processes of crocodilians. This includes lingering questions as to the extent of any terrestrial habitus. A direct morphological signal for locomotion can be expected in the postcrania, particularly the girdles and the limbs of the appendicular skeleton. After a lengthy survey, enough materials of the pelvic girdle are available to chart morphological variation in the subfamily from Eocene through to middle Miocene. Over this period, the pelvis has undergone a vigorous morphological radiation. An enclosed, ventrally oriented acetabulum in the ilium developed in one lineage that apparently recapitulates the pillar-erect configuration of the pelvic girdle seen in many Mesozoic crocodilian lineages, suggesting consistent use of erect high-walk in these mekosuchines. Other pelves from Oligo–Miocene deposits display morphology closer to modern crocodilians despite clearly representing derived forms themselves, indicating a partition of locomotory strategy in the fauna during the Oligo–Miocene. While materials of hindlimb remain frustratingly lacking in light of this discovery, enough materials of forelimb humeri have been uncovered to chart the morphological variation in the subfamily from Eocene through to Pleistocene, corroborating what is seen in the pelvic girdle. As such, a collaborative project has been started that aims to quantitatively asses shape and stress variation in the mekosuchine forelimb using geometric morphometric and finite element analyses.

Elephant dung, chewed antlers, weathered bones: documenting a unique taphonomic collectionhttps://peerj.com/preprints/32802017-09-222017-09-22Spyridoula PappaNeil AdamsPhilippa BrewerSimon ParfittGillian CarnegieMark Lewis
The Antony John Sutcliffe Collection is a unique taphonomic reference collection held within the Department of Earth Sciences at the Natural History Museum (NHM). Sutcliffe was the Curator of Fossil Mammal at the NHM from 1957 to 1987, during which time he collected a large assemblage of modern comparative vertebrate material, including complete skulls, bones, teeth and soft tissues (skin and faeces) of numerous species from across the world including sites in East Africa, Canada, Alaska, Siberia and northwest Europe. Sutcliffe studied Pleistocene mammals and was particularly interested in the alterations to their remains after death and how they come to be fossilised, i.e., their taphonomy.
The specimens were either collected during Sutcliffe’s own fieldwork or gifted to him by international colleagues, and are often accompanied by detailed notes on their provenance and original letters of donation.
After a preliminary study in 2013, and given the value of the collection for future taphonomic studies, a curatorial project ran from 2015 to 2017 aiming to document the entire collection on EMu (the museum’s collection management system), recording the anatomy, taxonomy, previous and new locations within the museum, and any associated documentation of over 1500 specimens. Photographs of each object were included and all specimens have been registered, safely repacked and rehoused at Wandsworth museum store, where they are now accessible to researchers. The specimens have the potential to form curated taphonomic reference standards for use by researchers around the world.

The Antony John Sutcliffe Collection is a unique taphonomic reference collection held within the Department of Earth Sciences at the Natural History Museum (NHM). Sutcliffe was the Curator of Fossil Mammal at the NHM from 1957 to 1987, during which time he collected a large assemblage of modern comparative vertebrate material, including complete skulls, bones, teeth and soft tissues (skin and faeces) of numerous species from across the world including sites in East Africa, Canada, Alaska, Siberia and northwest Europe. Sutcliffe studied Pleistocene mammals and was particularly interested in the alterations to their remains after death and how they come to be fossilised, i.e., their taphonomy.

The specimens were either collected during Sutcliffe’s own fieldwork or gifted to him by international colleagues, and are often accompanied by detailed notes on their provenance and original letters of donation.

After a preliminary study in 2013, and given the value of the collection for future taphonomic studies, a curatorial project ran from 2015 to 2017 aiming to document the entire collection on EMu (the museum’s collection management system), recording the anatomy, taxonomy, previous and new locations within the museum, and any associated documentation of over 1500 specimens. Photographs of each object were included and all specimens have been registered, safely repacked and rehoused at Wandsworth museum store, where they are now accessible to researchers. The specimens have the potential to form curated taphonomic reference standards for use by researchers around the world.

The most complete ankylosaur skull ever found in the Wessex Sub-basin (Lower Cretaceous) of the Isle of Wight.https://peerj.com/preprints/32772017-09-212017-09-21Stuart Pond
Ankylosaur remains are frequently recovered from the Lower Cretaceous Wealden deposits of the Isle of Wight, although the vast majority of these fossils represent postcranial elements and osteoderms. The rarity of ankylosaur cranial material means any new specimens are important for understanding the morphology, palaeoecology and evolution of these taxa. Here we describe a well-preserved partial ankylosaur cranium recovered with associated ankylosaur remains from the Wessex Formation at Compton Bay. This is the most complete ankylosaur skull ever recovered from the Wessex Sub-basin and is now held at Dinosaur Isle Museum (DI), Sandown, IOW. A highly water worn specimen held at the Sedgwick Museum of Earth Sciences was found at Chilton Chine in the early 1990s and assigned to cf. Polacanthus, and the two crania are compared here.
The specimen consists of the posterior part of the basicranium and skull roof including the proximal paraoccipital processes, occipital condyle and basal tuberosity. Both skulls share characters including the position of some of the foramina exiting the endocranium and lateral curvature of the skull roof. The DI skull differs from the Sedgwick specimen by the presence of a well-defined, notched border of the supraoccipital, flat rostal-caudal dorsal cranial surface, the occipital condyle being more bulbous and angled more ventrally, a well-defined nuchal shelf and being smaller and less robust. Differences between the specimens may be due to sexual dimorphism, ontogeny or they may represent different taxa.

Ankylosaur remains are frequently recovered from the Lower Cretaceous Wealden deposits of the Isle of Wight, although the vast majority of these fossils represent postcranial elements and osteoderms. The rarity of ankylosaur cranial material means any new specimens are important for understanding the morphology, palaeoecology and evolution of these taxa. Here we describe a well-preserved partial ankylosaur cranium recovered with associated ankylosaur remains from the Wessex Formation at Compton Bay. This is the most complete ankylosaur skull ever recovered from the Wessex Sub-basin and is now held at Dinosaur Isle Museum (DI), Sandown, IOW. A highly water worn specimen held at the Sedgwick Museum of Earth Sciences was found at Chilton Chine in the early 1990s and assigned to cf. Polacanthus, and the two crania are compared here.

The specimen consists of the posterior part of the basicranium and skull roof including the proximal paraoccipital processes, occipital condyle and basal tuberosity. Both skulls share characters including the position of some of the foramina exiting the endocranium and lateral curvature of the skull roof. The DI skull differs from the Sedgwick specimen by the presence of a well-defined, notched border of the supraoccipital, flat rostal-caudal dorsal cranial surface, the occipital condyle being more bulbous and angled more ventrally, a well-defined nuchal shelf and being smaller and less robust. Differences between the specimens may be due to sexual dimorphism, ontogeny or they may represent different taxa.